Question

How can I disable the left-bottom error message within the video element in a win8 app?

Answer 1

I think you need to provide a bit more information about what exactly are you trying to do ?
As of now, I think providing the correct video source will help with removing the error message.

<video id="video" width="320" height="240" controls="controls">
        <source src="Videos/abc.mp4" type="video/mp4" />    
</video>

Where Videos is a folder in the project package and abc.mp4 is the video file inside the Videos folder.
Hope this helps 🙂